Buggy code:
@ Override public void visit ( Tree . Satisfies that ) { } @ Override public void visit ( Tree . InOp that ) { } @ Override public void visit ( Tree . LetExpression that ) { } @ Override public void visit ( Tree . BaseType that ) { } @ Override public void visit ( Tree . QualifiedType that ) { } private void checkBaseVisibility ( Node that , TypedDeclaration member , String name ) { } private void checkQualifiedVisibility ( Node that , TypedDeclaration member , String name , String container , boolean selfReference ) { } private void checkBaseTypeAndConstructorVisibility ( Tree . BaseTypeExpression that , String name , TypeDeclaration type ) { } private void checkQualifiedTypeAndConstructorVisibility ( Tree . QualifiedTypeExpression that , TypeDeclaration type , String name , String container ) { } private static String baseDescription ( Tree . BaseType that ) { } private static String qualifiedDescription ( Tree . QualifiedType that ) { } @ Override public void visit ( Tree . BaseMemberExpression that ) { } private void checkExtendsClauseReference ( Tree . BaseMemberOrTypeExpression that , Declaration member ) { } private void visitGenericBaseMemberReference ( Tree . StaticMemberOrTypeExpression that , TypedDeclaration member ) { } private TypedDeclaration resolveBaseMemberExpression ( Tree . BaseMemberExpression that , boolean error ) { } @ Override public void visit ( Tree . QualifiedMemberExpression that ) { } private void visitGenericQualifiedMemberReference ( Tree . QualifiedMemberExpression that , Type receiverType , TypedDeclaration member ) { } private void handleStaticReferenceImplicitTypeArguments ( Tree . QualifiedMemberOrTypeExpression that ) { } private TypedDeclaration resolveQualifiedMemberExpression ( Tree . QualifiedMemberExpression that , boolean error ) { } private boolean isSelfReference ( Tree . Primary p ) { } private void checkSuperMember ( Tree . QualifiedMemberOrTypeExpression that ) { } private void visitQualifiedMemberExpression ( Tree . QualifiedMemberExpression that , Type receivingType , TypedDeclaration member , List < Type > typeArgs , Tree . TypeArguments tal ) { } private static Type accountForGenericFunctionRef ( boolean directlyInvoked , Tree . TypeArguments tas , Type receivingType , List < Type > typeArgs , Type fullType ) { } private void checkSpread ( TypedDeclaration member , Tree . QualifiedMemberExpression that ) { } private Type accountForStaticReferenceReceiverType ( Tree . QualifiedMemberOrTypeExpression that , Type receivingType ) { } private Type accountForStaticReferenceType ( Tree . QualifiedMemberOrTypeExpression that , Declaration member , Type type ) { } private Type getStaticReferenceType ( Type type , Type rt ) { } private void visitBaseMemberExpression ( Tree . StaticMemberOrTypeExpression that , TypedDeclaration member , List < Type > typeArgs , Tree . TypeArguments tal , Type receivingType ) { } @ Override public void visit ( Tree . BaseTypeExpression that ) { } private void visitGenericBaseTypeReference ( Tree . StaticMemberOrTypeExpression that , TypeDeclaration type ) { } private TypeDeclaration resolveBaseTypeExpression ( Tree . BaseTypeExpression that , boolean error ) { } private boolean checkConcreteConstructor ( TypedDeclaration member , Tree . StaticMemberOrTypeExpression that ) { } private boolean checkConcreteClass ( TypeDeclaration type , Tree . MemberOrTypeExpression that ) { } private boolean checkSealedReference ( TypeDeclaration type , Tree . MemberOrTypeExpression that ) { } void visitExtendedTypePrimary ( Tree . ExtendedTypeExpression that ) { Declaration dec = that . getDeclaration ( ) ; if ( dec instanceof Class ) { Class c = ( ( Class ) ( dec ) ) ; if ( c . isAbstraction ( ) ) { Declaration result = findMatchingOverloadedClass ( c , that . getSignature ( ) , that . getEllipsis ( ) ) ; if ( ( result != null ) && ( result != dec ) ) { TypeDeclaration td = ( ( TypeDeclaration ) ( result ) ) ; that . setDeclaration ( td ) ; c = ( ( Class ) ( td ) ) ; if ( isOverloadedVersion ( result ) ) { if ( ( result . isPackageVisibility ( ) ) && ( ! ( AnalyzerUtil . declaredInPackage ( result , unit ) ) ) ) { that . addError ( ( ( "package<seq2seq4repair_space>private<seq2seq4repair_space>constructor<seq2seq4repair_space>is<seq2seq4repair_space>not<seq2seq4repair_space>visible:<seq2seq4repair_space>'" + ( result . getName ( ) ) ) + "'" ) ) ; } } } } <START_BUG> if ( ( c . getParameterList ( ) ) == null ) { <END_BUG> that . addError ( ( ( "class<seq2seq4repair_space>cannot<seq2seq4repair_space>be<seq2seq4repair_space>instantiated:<seq2seq4repair_space>'" + ( c . getName ( unit ) ) ) + "'<seq2seq4repair_space>does<seq2seq4repair_space>not<seq2seq4repair_space>have<seq2seq4repair_space>a<seq2seq4repair_space>parameter<seq2seq4repair_space>list<seq2seq4repair_space>or<seq2seq4repair_space>default<seq2seq4repair_space>constructor" ) ) ; } } } @ Override public void visit ( Tree . QualifiedMemberOrTypeExpression that ) { } void resetSuperReference ( Tree . QualifiedMemberOrTypeExpression that ) { } @ Override public void visit ( Tree . QualifiedTypeExpression that ) { } private void visitGenericQualifiedTypeReference ( Tree . QualifiedTypeExpression that , Type outerType , TypeDeclaration type ) { } private TypeDeclaration resolveQualifiedTypeExpression ( Tree . QualifiedTypeExpression that , boolean error ) { } private static boolean checkMember ( Tree . QualifiedMemberOrTypeExpression qmte ) { } private static boolean isResolvedStaticMethodRef ( Tree . QualifiedMemberOrTypeExpression qmte ) { } private TypeDeclaration getDeclaration ( Tree . QualifiedMemberOrTypeExpression that , Type pt ) { } private boolean explicitTypeArguments ( Declaration dec , Tree . TypeArguments tal ) { } private boolean typeConstructorArgumentsInferrable ( Declaration dec , Tree . StaticMemberOrTypeExpression smte ) { } @ Override public void visit ( Tree . SimpleType that ) { } @ Override public void visit ( Tree . EntryType that ) { } private void visitQualifiedTypeExpression ( Tree . QualifiedTypeExpression that , Type receivingType , TypeDeclaration memberType , List < Type > typeArgs , Tree . TypeArguments tal ) { } private void visitBaseTypeExpression ( Tree . StaticMemberOrTypeExpression that , TypeDeclaration baseType , List < Type > typeArgs , Tree . TypeArguments tal , Type receivingType ) { } @ Override public void visit ( Tree . Expression that ) { } @ Override public void visit ( Tree . Outer that ) { } @ Override public void visit ( Tree . Super that ) { } @ Override public void visit ( Tree . This that ) { }

Fix:
if ( ( ! ( c . isAbstraction ( ) ) ) && ( ( c . getParameterList ( ) ) == null ) ) {